相关图片 [图片][图片]分布与危害 #二星叶蝉 学名ErythroneuraapicalisNawa。别名二点浮尘子、二点叶蝉。主要分布在我国东北、华北、华东、西南等地。除为害菊花外，还为害大丽花、一串红、桃花等。 该虫主要为害叶片，受害叶片会失绿呈小白点，随着受害的严重程度，白点汇集成大斑。严重时叶片呈苍白色，提早脱落。 形态特征 成虫：体长3-4毫米，有红褐和黄白色两种。以黄色种为多。前胸背板前缘有圆形小黑丝3枚，排成1列；盾板上有两个大型黑斑，所以称作二星叶蝉。前翅斑纹不规则，且浓淡不一；后翅无端脉。 卵：黄白色，长椭圆形，稍弯曲，长约0.5毫米。 若虫：体色有两型：红褐色型，有尾部常向上举，成熟时体长2毫米。 发生规律 该虫年发生3代，以成虫在石缝、杂草丛中越冬。翌年4月开始活动产卵。卵散产于菊花叶背叶脉内或绒毛下。第一代若虫5月下旬-6月中旬为盛孵期；第二代若虫于7月上旬至8月上旬发生；第三代若虫发生在9月上旬至10月下旬。黄白色型若虫比红褐色型若虫早发生2周。前者第一代成虫在6月上旬羽化；后者第一代成虫在6月下旬羽化。成虫和若虫均在叶背取食，严重时叶片呈苍白色，提早枯萎脱落。 防治方法 （1）秋后清扫落叶，铲除杂草，减少和消除越冬成虫。 （2）防治药剂：使用50%啶虫咪水分散粒剂（国光崇刻）3000倍液，10%吡虫啉可湿性粉剂（如国光毙克）1000倍液，40%啶虫.毒乳油（如国光必治）1500-2000倍液，或啶虫咪水分散粒剂（国光崇刻）3000倍液+5.7%甲维盐乳油（国光乐克）2000倍混合液喷雾均可针对性防治。

HESE small, soft-bodied, pear-shaped insects cluster densely on tender new growth and the undersides of leaves to suck plant juices. Plants often can withstand some aphid feeding with no adverse effect, but badly infested plants develop distorted growth and leaves may turn yellow or drop off. [图片]Sometimes it takes close inspection to discover an aphid infestation. They blend in so well with foliage that you may not spot them at first glance, even though hundreds are present. Many species of aphids feed on home garden plants; these insects range in color from pale green, pink, or black to red or yellow. Size is typically 1/16″–1/4″. Adult aphids are generally wingless, but winged adults will appear when overcrowded. Immature aphids (nymphs) closely resemble adults. [图片]Both adults and nymphs feed on a wide variety of plants, including most edibles and ornamentals. In small numbers aphids do little damage, but they are able to reproduce rapidly and can quickly become a more serious problem. Also, as they feed, aphids secrete a sweet fluid called honeydew that can attract ants; sooty black fungus may grow on coated leaves. Aphids are common throughout the U.S. [图片]Prevention and control When fertilizing your garden, avoid applying too much nitrogen, which can stimulate plants to grow too rapidly and produce a flush of exactly the kind of tender new growth that aphids love. Attract and release beneficial insects, such as ladybugs and lacewings, which will be happy to devour a bountiful supply of aphids. Use a spray with neem oil, which is derived from the seed of the neem tree. It controls a wide variety of common garden insect pests such as aphids as well as fungal diseases. Use a strong spray of water from your hose to dislodge aphids from affected plants. This will reduce their numbers dramatically. Recheck the plants a few days later and repeat the treatment if needed. (Keep in mind that water sprays will also kill beneficial insects.)

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相关图片 [图片][图片]分布与危害 #刺足根螨 学名Rhizoglyhusechinopus，别名球根粉螨、葱螨，属于蜱螨目，粉螨科，是球根花卉的重要害虫。主要为害百合、郁金香、水仙、菖兰、葱兰、风信子、苏铁等花卉。 该螨是以成、若螨刺吸球根鳞片及块根为害，当鳞片腐烂便集中于腐烂处取食，会有汁液流出的现象，造成组织坏死，表面变褐腐烂，肉质鳞片干缩，破裂成似木栓化的碎片。导致地上部植株矮小、瘦弱，花为畸形，且小，严重影响花卉的观赏价值。 形态特征 成螨：雌螨体长0.58-0.87毫米，卵圆形，白色发亮。螯肢和附肢浅褐色；前足体板近长方形；后缘不平直；基节上毛粗大，马刀形。格氏器官末端分叉。足短粗，跗节Ⅰ、Ⅱ有一根背毛呈圆锥形刺状。雄螨体长0.57-O.8毫米。体色和特征相似于雌螨，阳茎呈圆筒形。跗节爪大而粗，基部有一根圆锥形刺 卵：长0.2毫米，椭圆形，乳白色半透明。 若螨：体长0.2-0.3毫米，体形与成螨相似，颗体和足色浅，胴体呈白色。 发生规律 该螨年发生9-18代，主要是以成螨在病部及土壤中越冬，尤其是腐烂的鳞茎残瓣中最多，两性生殖。该螨喜高温高湿的环境，在适宜的条件下繁殖快。雌螨交配后1-3天开始产卵，卵期3-5天。1龄和3龄若螨期，遇到不适条件时，出现体形变小的活动化播体。若螨和成螨开始多在块根周围活动为害，当鳞茎腐烂便集中于腐烂处取食。该螨既有寄生性也有腐生性，有很强的携带腐烂病菌和镰刀菌的能力。高温高湿干旱对其生存繁殖不利。在16℃至26℃和高湿下活动最强，造成的伤口为真菌、细菌和其他有害生物侵入提供了条件。 防治方法 （1）加强栽培管理，高温季节深耕暴晒，消灭大量根螨，栽种前对土壤严格消毒。 （2）不宜连作，可减少虫源。 （3）种植前可对鳞茎进行挑选，选择无虫的鳞茎种植。在储藏百合时室内要保证通风干燥，这样可以抑制根螨的生长和繁殖。 （4）对鳞茎进行消毒，可用1000倍液50%乙酯杀螨醇喷注鳞茎，或将被害鳞茎放在稀石灰水中浸泡10分钟，取出冲洗干净，阴干后使用。

相关图片 [图片][图片]分布与危害 #卵形短须螨 学名BrevipapusobovatusDonnadieu，该虫分布广泛，在我国华东、华中、华南等地均有发生，为害严重。寄主主要有非洲菊、大丽花、满天星、白兰、石榴等。 为害时一般表现在叶背，使叶反面产生油渍状的紫褐色斑块，叶柄紫褐色，易早落。 形态特征 成螨背部具网状纹，中央网纹不明显。后半部具5对背毛，须肢4节。雌螨体长0.293毫米，体宽0.167毫米，椭圆形，背腹扁平，暗红色，有不规则的黑色斑块。雄螨体长0.232毫米，宽0.15毫米。体型比雌螨细长。后半体的网状纹在前部和亚侧部比较明显。后足体与末体之间有1横纹区分开。 若螨椭圆形，末体较前足狭窄，背面无网状纹，仅在后足体具横向皱纹。背毛呈阔披针形，具锯齿腹面的生殖板未分化。 发生规律 1年发生6-7代，以橙红色的雌螨群集植株根系越冬，或在叶反面、腋芽等处越冬。春季气温达15°时，雌螨出蛰，爬至叶片上取食产卵。约40天完成1代7-9月为发生高峰期。 防治方法 （1）增施肥料，增强植株的抵抗力。冬季清洁园地，减少越冬虫源。越冬前可喷施波美0.3-0.5度石硫合剂。 （2）使用10%苯丁哒螨灵乳油(如国光红杀)1000倍液或10%苯丁哒螨灵乳油(如国光红杀)1000倍液+5.7%甲维盐乳油（如国光乐克）3000倍液混合后喷雾防治，建议连用2次，间隔7-10天。

相关图片 [图片][图片]分布与危害 #李短尾蚜 学名BrachycaudushelichrysiKaltenbach,又名李圆尾蚜。属同翅目，蚜科。主要分布在上海、江苏、浙江、四川、辽宁等。寄主有瓜叶菊、金盏菊、西蕃莲、松果菊、天人菊、桃、李、山杏、杏梅、兰绒球等。 该蚜主要在春夏季群集为害金盏菊植株，以吸食汁液为害，影响植株的正常生长、开花。 形态特征 无翅胎生雌虫体长1.6毫米，宽0.8毫米，淡黄至黄绿色，无明显的斑纹。腹管灰褐色，短。尾片灰黑色。有翅胎生雌虫体绿色，长1.7毫米，宽0.8毫米。腹部色淡，有黑色斑纹。 发生规律 1年发生多代，在江浙一带1年发生10多代，以卵在梅、李等木本植物上越冬。次年春越冬卵孵化、在越冬寄主的新叶、新芽上吸食。5—6月产生有翅胎生蚜，迁往金盏菊上为害。以孤雌胎生方式繁殖，直到10月中旬再回越冬寄主上，产生两性蚜，交尾产卵越冬。 防治方法 （１）种植时远离栽种蔷薇科植物如梅、李等园地，减少越冬虫源。 （２）保护利用天敌如瓢虫、草蛉、食蚜蝇等。 （３）在早春花木发芽前用清水冲洗枝干和芽部，把越冬卵和初孵若虫冲刷掉。清除周围杂草。 （４）化学防治蚜虫繁殖快，世代多，用药易产生抗性。选药时建议用复配药剂或轮换用药，可用50%啶虫咪水分散粒剂（国光崇刻）3000倍液，10%吡虫啉可湿性粉剂（如国光毙克）1000倍液，40%啶虫.毒乳油（如国光必治）1500-2000倍液，或啶虫咪水分散粒剂（国光崇刻）3000倍液+5.7%甲维盐乳油（国光乐克）2000倍混合液喷雾均可针对性防治，防治时建议在常规用药基础上缩短用药间隔期，连用2-3次。

Although an infestation of armyworm caterpillars can rapidly decimate a commercial field crop, they rarely cause this degree of destruction in home gardens. Armyworms feed at night on plant foliage and grass blades; they hide under foliage and debris during the day. Severe feeding can result in dead areas of lawn and ragged-looking or defoliated crops. [图片]Young armyworms are pale green; older larvae are brownish with stripes along their bodies. Several species attack a variety of garden crops, including corn, beets, tomatoes, peppers, potatoes, onions, and peas. Adults are gray-brown moths that migrate northward in the spring to lay eggs on host plants and in lawns. There can be several generations each year; each generation emerging farther north. Late-season generations will also feed on fruit. [图片]In general, armyworms do not survive cold winters, but they can be a year-round pest in warm-winter climates, such as California and Florida. Beet armyworms are a problem in southern states and in the West, where they can be found as far north as Montana. [图片]Prevention and Control Encourage native beneficial insects such as parasitic wasps that prey on caterpillars. Weed out grassy weeds as well as pigweed, plantain, and lamb’s quarters, which are host plants for the beet armyworm.

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When this bacterial disease infects young cabbage-family plants, the leaves turn yellow and plants become stunted and die. In older plants, first signs of infection are usually on the lower leaves, which develop yellow, V-shaped lesions at their edges. The infection gradually spreads toward the center of the leaf, and the veins within this dead tissue turn black. As the disease progresses, the heads of cabbage and cauliflower may rot. [图片]The bacterium is spread by insects and splashing water and on contaminated tools. Warm, humid weather encourages the disease, which occurs in most of North America, but is most common in the East. [图片]Prevention and Control Plant certified disease-free seed and transplants. When possible, choose varieties that are resistant to black rot. If space in your garden allows, follow a three- to four-year crop rotation to avoid planting susceptible crops in the same area. Use drip irrigation or soaker hoses rather than overhead watering to keep foliage dry. Destroy or deeply bury infected plants.

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Symptoms of this fungal disease vary with the crop. Beans develop round, black, sunken spots on the pods and stems; on leaf undersides, veins turn black. When the fungus infects cucumbers and melons, the leaves develop yellow spots that dry up and flake away; spots on watermelon leaves are black. Infected fruits develop sunken areas with dark borders. On tomato plants, ripe fruit develops sunken spots with dark centers. [图片]Anthracnose can also develop in other vegetable crops and in strawberries. Wind and wet weather fosters the spread of infection. Anthracnose overwinters in plant residues in the soil. It is an especially troublesome disease in hot, humid regions. [图片]Prevention and Control Plant resistant varieties such as Calypso cucumber and Charleston Gray watermelon. Different species of fungi cause anthracnose in different crops. Thus, if you had anthracnose on your tomatoes last year, there’s no harm in planting beans in that bed this year. It can be helpful to wait two years before replanting tomatoes in that bed, though. Use drip irrigation or soaker hoses rather than overhead watering. Avoid disturbing plant foliage when it’s wet. Harvest tomato and pepper fruits promptly and wash and dry them immediately to remove any fungal spores on the fruit surface. Clean up crop debris in fall.

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Water-soaked spots on blossoms or leaves are an early symptom of this fungal disease. A cottony white growth may develop on the spots. White mold attacks many types of edible plants, including beans, peas, potatoes, soybeans, carrots and cabbage. White mold gradually spreads to all above-ground plant parts. Infected tissues wilt, yellow and die. Cool, wet weather favors the development of the disease. The fungus overwinters in the soil. [图片]Prevention and Control Choose disease-resistant varieties when possible. Space plants and rows widely so that plants remain dry as much as possible. Avoid handling plants when wet.[图片]Water early in the day so plants dry before nightfall. Use drip irrigation or soaker hoses rather than overhead watering. Minimize the use of nitrogen fertilizers. Uproot and destroy diseased plants as soon as you notice them.

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Leaves with gray-brown areas surrounded by a dark or yellowish margin are one of the early symptoms of this fungal disease. These discolored areas lack the concentric rings characteristic of early blight, but they may be filled with many small, black spores. Symptoms generally appear on lower leaves first. The fungus can infect a wide variety of plants. In a severe outbreak, septoria leaf spot fungi may also attack seedlings. [图片]The disease is most problematic in cool, wet weather. The fungus overwinters on plant debris in the soil and on weeds such as jimsonweed, horsenettle and nightshade. [图片]Prevention and Control Plant disease-free seed. Rotate crops to avoid growing susceptible plants in the same area year after year. Pick off and destroy any infected leaves. Mulch around the plants to reduce soil splashing, which can spread the disease. Use drip irrigation or soaker hoses rather than overhead watering. In the fall, remove any diseased plant material and destroy it.

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